Reproducer arm



May 27, 1930. A. N. GOLDSMITH REPRODUC ER ARM Filed July 29 1925INVENTOR ALFRED. N. GOLDSMITH TORNEY Patented May 27, 1930 UNITED STATESPATENT OFFICE ALFRED N. GOLDSMITH, OF MOUNT VERNON, NEW YORK, ASSIGNORTO RADIO COR- PORATION OF AMERICA, A CORPORATION OF DELAWARE REPRODUCERARM Application filed July 29, 1925. Serial No. 46,702.

My invention relates to reproducers commonly used with phonographs inconnection with radio receiving circuits. It has for its object theadaptation, improved operation and simplification of apparatus commonlyused with these two types of devices.

For further object it is intended to aid in the manipulation, adjustmentand modification of tone which is derived from a phonom graph in asimpler and more eflicient manner than heretofore.

It is well known that an ordinary phonograph is incapable of accurateand minute adjustment by the means furnished with the instrument andparticularly so for a person not skilled in the art. My device furnishesmeans which are simple, readily accessible and easily operated. Iaccomplish this by locating the tone modifier in the shape of Variableinductance, transformer or potentiometer in a portion of the tone arm orbase where it can be reached and manipulated easily. This modifier actsupon a current which is generated directly from the reproduoing deviceitself. The reproducing device has an electromagnetic arrangement whichproduces currents according to the sound vibrations. It can be seen inthis way that any changes in the control of the output circuit throughsuch a modifier may directly effect any apparatus which is attached toit.

Further and more definite objects may be observed in connection with theannexed drawing, specification and claims.

Fig. 1 of the drawing shows my reproducer, tone arm and support combinedwith the tone modifier.

Fig. 2 shows a detail of the reproducer.

Fig. 3 shows a section taken on line III-III of the reproducer.

1 shows the electromagnetic arrangement for sending electric currentscorresponding to the tone according to the motions of needle 9 on therecord 15. This needle is held in socket 10 or by any other suitablemeans.

3 is a pivoted connection to a rotatable tone arm 16 having acounter-weight 2 mounted on the opposite side from the reproducer 1 inorder to counteract some of the weight on the record 15. 16 is free tonicnt of this apparatus and the result is indicated on the scale 19.

Current which is generated in the reproducer 1 is carried along theconductor 17 and into the current varying apparatus 6. Here theconductivity, or the coupling, as the case may be, is varied accordingto the setting on the indicator 19 and the resultant current is sent outon the conductor 7 to suitable amplifiers or loud speakers as desired.

8 in Fig. 2 shows the shape of the permanent magnet which causes a flowof current in the coil 20 as the armature 11 vibrates back and forthbetween its respective pole pieces 12 and 13 according to undulations orvariations in the record 15. The coil 20 is more clearly shown in Fig.3. '14 is a flexible mounting piece to allow the armature 11 to vibratein theproper way.

In the ordinary phonograph reproducing horn, the volume and quality ofthe tone is often times modified by introducing a sound absorbing bodyinto the throat of the horn by means of a simple shutter. Thedisadvantage of this arrangement is that it produces reverberation andundesirable resonance periods from such stoppage or reflection of thesound waves. The only way of regulating the actual volume of soundproduced is by changing the size and stiffness of the reproducing needleas at 9. This method, too, has its disadvantages which will not bediscussed in detail here. It is sufficient to say, however, that aneedle of one particular size produces the best results.

lVith this invention a proper size needle may be always used and adirect control of the sound output without resonance, undesirablereverberations or other disagreeable results is possible. It has alsobeen found that the mounting pedestal as 5, should have a large flaringbase in order to give it sufficiently rigid support upon its mountingboard. In most all casesthis base is made hollow in order .to give therequisite rigidity and to conduct away the sound as has been the customin the ordinary phonograph. It thus provides convenient location of anysound modifying apparatus.

It hasbeen found that this apparatus may be installed in the ordinarytype of phonograph without much difiiculty. It requires only thesubstitution of the electromagnetic reproducer in place of the diaphragmreproducer and the drilling of mounting holes for the modifyingapparatus in thixpedestal. The conducting wire 17 can be run through theordinary tone arm in the space provided for conducting sound.

In Patent No. 1,677 ,806, granted July 1'}, I

1928, assigned to the same assignee there is described a method ofcontrolling and modifying the tone of electrical phonographs and thecircuits therefor. In the present application I desire to claim theincorporation of such apparatus in an electrical phonograph and thestructural arrangement therefor.

' Thus having described my invention, I do not wish to be limited to theexact modification shown but only in so far as it would'involveinvention to substitute equivalent elements or arrangements of thoseshown and as indicated in the following claims 1. In a phonograph thecombination of, an electromagnetic reproducer, a reproducer arm andpedestal,-an electro-magnetic controlling means constructed and arrangedto control the output of said. electro-magnetic reproducer, said meansbeing mounted within said pedestal, means carried by said pedestal tovary the controlling means, and means associated with said lastmentioned means to indicate the character of adjustment on saidcontrolling means.

2. In a phonograph the combination of,

an electromagnetic reproducer, a reproducer arm and pedestal,controlling means constructed and arranged to control the output of saidelectro-m'agnetic reproducer, said means being mounted-within saidpedestal, means carried by said pedestal to vary the controlling means,and means associated with said last mentioned means to indicate thecharacter of adjustment on said controlling means.

7 ALFRED N. GOLDSMITH.

